This invention relates generally to an apparatus for the liquid treatment of pulp, and more specifically to a liquid treatment system where vapour and liquid are discharged separately.
This invention relates to an apparatus for the liquid treatment of pulp, comprising a stand with two end rolls, over which an endless liquid permeable web runs. The web consists of a wire or perforated belt, for example steel belt. The web is driven by one of the end rolls and slides over perforated covers on containers located therebeneath. A head box for the supply of pulp is located at one end of the web, and means for the transfer of the treated pulp are located at the other end of the web. Means for supplying treatment liquid to the pulp are located above the web. The containers located beneath are intended for the collection of liquid.
The said containers extend in cross-direction along the entire width of the web and are arranged one after the other in the running direction of the web. The width of the web, and therewith also of the containers, can be up to 6 m. In certain cases webs of still greater width are used. The containers may also be sections of a greater trough.
At the liquid treatment liquid in the pulp is driven out by supplied treatment liquid. The liquid driven out together with vapours and gases are collected in the containers.
It is desired to discharge vapours and liquid from the containers separately. This, however, involves difficulties, due to the extension of the containers in the cross-direction of the web and to the restricted space in the containers, which implies that the flow rate of the vapours is high and foam formation easily arises.
The present invention has the object to solve this problem. According to the invention, a very compact structural design in combination with low vapour rate and reduced risk of foam formation in the containers is obtained. The characterizing features of the invention are apparent from the attached claims.